Railway vehicle truck bolsters of different manufacture origin and also of different vehicle capacity may vary in contour and/or shape. This difference in shape has required that the air brake assemblies, for braking the truck wheels, which are normally mounted on the bolster be attached by fabricated parts of different construction. Such fabrication oftentimes used tie bolts and space bars and under some circumstances interfered with the installation of well-known auxiliary car control devices. The fabrication and different mounting arrangements tended to increase the installation and maintenance costs of the air brake assembly due to the additional parts required for mounting to the truck bolster. In addition, parts could not be pre-manufactured since many of the items required custom fitting to the various contours and hole locations of truck bolsters. Split orders from a customer often required two different attachments, thus interchangeability was not possible.